Apparatus and method for heating an outdoor area

ABSTRACT

An outdoor firepit comprises a vessel adapted to contain a combustible material. A plurality of conduits are within the vessel and are positioned to be in thermal communication with the combustible material. An air source forces air through the plurality of conduits and into an area surrounding the firepit. An apparatus for heating an outdoor area comprises a vessel adapted to contain a combustible material having an inner bowl and an outer bowl and a space therebetween. A plurality of conduits are within the vessel adjacent the inner bowl and are positioned to be in thermal communication with the combustible material. An air source forces air through the plurality of conduits and into the outdoor area surrounding the vessel.

BACKGROUND

1. Technical Field

This invention relates to apparatus and method for heating an outdoor area.

2. Description of the Related Art

Outdoor patio fireplaces, heaters, and firepits are used to heat ambient air in selected outdoor areas. These units commonly use radiant heating to heat the area surrounding such a heater. Any convective heating is primarily due to wind currents. As such, the heating effect is primarily limited to areas in close proximity to the heater.

There is a demonstrated need for an outdoor firepit that provides an enhanced heating area around the firepit.

SUMMARY

The following presents a general summary of several aspects of the present invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to limit the scope of the claims. The following summary merely presents some concepts of the invention in a general form as a prelude to the more detailed description that follows.

In one aspect, an outdoor firepit comprises a vessel adapted to contain a combustible material. A plurality of conduits is located within the vessel and is positioned to be in thermal communication with the combustible material. An air source forces air through the plurality of conduits and into an area surrounding the firepit.

In another aspect, an apparatus for heating an outdoor area comprises a vessel adapted to contain a combustible material having an inner bowl and an outer bowl and a space therebetween. A plurality of conduits is located within the vessel adjacent the inner bowl and is positioned to be in thermal communication with the combustible material. An air source forces air through the plurality of conduits and into the outdoor area surrounding the vessel.

In yet another aspect, a method of heating an outdoor area comprises disposing a plurality of conduits in a vessel. A combustible material is combusted in thermal contact with the plurality of conduits in the vessel. Air is forced through the plurality of conduits such that the air exiting the plurality of conduits heats an area surrounding the vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

For detailed understanding of the illustrative embodiments, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:

FIG. 1 is a cross-section view of one embodiment;

FIG. 2A is a perspective view of one illustrative example of the present invention;

FIG. 2B is an exploded perspective view showing a flow manifold and bowl of the firepit of FIG. 2A;

FIG. 3A is a section view of one illustrative example of a flow conduit for use in one embodiment of the present invention;

FIG. 3B is a side view of an exit nozzle of a flow conduit of FIG. 3A;

FIG. 3C is a top view of an exit nozzle of a flow conduit of FIG. 3A;

FIG. 4A is a section view of another illustrative embodiment of the present invention;

FIG. 4B is a perspective view of an example flow conduit of FIG. 4A;

FIG. 5 is a sketch showing a non-limiting example of an air deflector in a nozzle in one embodiment;

FIG. 6 is a sketch of a dual-walled vessel having a flow conduit assembly according to one embodiment;

FIG. 7 is a sketch showing one non-limiting example of a firepit having an air-motor driven fan;

FIGS. 8A-8D show non-limiting examples of flow conduits at least partially formed in at least one wall of a firepit;

FIG. 9 shows a non-limiting example of a flow conduit arrangement;

FIG. 10 shows another non-limiting example of a flow conduit arrangement; and

FIG. 11 shows yet another non-limiting example of a flow conduit arrangement.

DETAILED DESCRIPTION

Described below are several illustrative embodiments of the present invention. They are meant as examples and not as limitations on the claims that follow. For purposes of this disclosure, the terms firepit, outdoor fireplace, patio heater, outdoor space heater, and outdoor heater are intended to mean the same.

According to one embodiment of the present invention, see FIGS. 1, 2A, 2B, a firepit 1 comprises a vessel such as bowl 4 suitable for containing a combustible material 10. As used herein, the term bowl includes any concave vessel suitable for containing the combustible material 10. Such shapes include, but are not limited to, rectangular vessels, square vessels, circular vessels, portions of oblate spheroids, and hemispherical vessels. Bowl 4 may be made of any suitable material for containing combusting materials. Such materials include but are not limited to, steel, stainless steel, copper, copper alloys, aluminum, aluminum alloys, ceramic, ceramic coated metal. Stone, masonry, and cement. The term combustible material includes, but is not limited to: wood, charcoal, coal, paper products, liquid and/or gas hydrocarbons, and any other suitable combustible material. In one embodiment, a thermal insulating material 9 is applied to the bottom surface of bowl 4 to reduce the heat loss through the bottom of bowl 4. Insulating material 9 may be applied by painting, spraying, dipping or any other suitable technique. Insulating material 9 may be made of a fibrous material, a cementitious material, or any other suitable material.

An inlet tube 12 is located in the bottom surface of bowl 4. Attached to inlet tube 12 is an air source 7 suitable for providing air at a positive pressure to inlet tube 12. In one embodiment, air source 7 is a squirrel cage fan providing an air flow 8 upward through inlet tube 12. As used herein, the term fan is intended to mean any bladed air moving device including, but not limited to, an axial fan, a centrifugal fan, an axial blower, a centrifugal blower, and any other suitable air moving device. A motor 11 is used to power air source 7. In one embodiment, motor 11 may be an electric motor powered by AC or DC current. Alternatively, motor 11 may be an air driven motor powered by a suitable air supply.

Air flow 8 from air source 7 is routed through flow conduits 6 placed within bowl 4. The flow conduits 6 may be part of a manifold assembly 15 (see FIGS. 2A and 2B). In one embodiment, as shown in FIGS. 1, 2A, and 2B, manifold assembly 15 is removable from inlet tube 12 for ease of cleaning of the firepit and for replacement of a worn and/or damaged manifold. Conduits 6 may be manufactured out of any suitable material, such as, for example, steel, stainless steel, copper, copper alloys, aluminum, aluminum alloys, ceramic, and ceramic coated metal. Heat generated by the combustion of combustible material 10 in bowl 4 is conducted through the walls of conduit 6 and is heats the air flow 8 by thermal conduction and convection. Air flow 8 exits conduit 6 at nozzle 19.

In one embodiment, see FIGS. 3A-3C, nozzle 19 may be shaped to accelerate air flow 8 as it exits nozzle 19. The accelerated air flow provides an enhanced heating effect at a substantial distance from the firepit. In one example, see FIG. 3 B, the top side 32 of conduit 19 converges toward the bottom side 33 by an angle α creating a reduced area nozzle causing the air flow 8 to accelerate at the exit of conduit 19. The angle α may be in the range of about 5 degrees to about 20 degrees. Alternatively, both top side 32 and bottom side 33 may converge.

FIG. 3C shows a top view of nozzle 19 where the sides 34 of nozzle 19 diverge at an angle β to spread the flow out to a larger horizontal zone in the vicinity of firepit 1. The angle β may be in the range of about 5 degrees to about 20 degrees. The angles α and β may be selected such that the net cross sectional area of conduit nozzle 19 reduces toward the exit such that the air flow 8 is accelerated as it flows toward the exit of conduit nozzle 19. Conduit nozzle 19 may be designed such that the exit velocity may be in the range of about 5 to about 40 feet per second.

In one illustrative embodiment, a deflector 30 is moveably attached by pin 31 near the exit to conduit nozzle 19 such that air flow 8 may be deflected by deflector 30 as air flow 8 exits conduit nozzle 19. Any suitable air deflector and attachment method is suitable for the present invention.

FIGS. 4A and 4B present another illustrative example of an embodiment of the present invention. As shown therein, firepit 25 has a dual-walled vessel 26 comprising an inner bowl 22 and an outer bowl 20 with a space 27 between the two bowls 22 and 20. The space between the bowls may be filled with an insulating material 24. Each bowl 22, 20 may be made of a material such as the materials previously described with respect to bowl 4 of FIG. 1. Each bowl 22, 20 may be made from a different material or both bowls may be made from the same material.

In one non-limiting example, insulation 24 may be a mineral material, including but not limited to: vermiculite, perlite, sand, and any mixture of these minerals. Alternatively, insulating material 24 may be crushed fiberglass. In yet another alternative, a gas such as air and/or nitrogen may be used as an insulator. In another alternative, the space 27 between the bowls may be evacuated such that a vacuum exists between the bowls 22, 20.

As shown in FIG. 4A, air flow 8 is directed through flow channels 23 along the surface of inner bowl 22 and out through conduit nozzle 19. One non-limiting example of flow channel 23 is shown in FIG. 4B. Flow channel 23 may have a flange 29 attached to each side. Flange 29 facilitates attachment of flow channel 23 to inner bowl 22. Such attachment technique may include, but is not limited to, seam welding, tack welding, brazing, soldering, riveting, any combination of these techniques, and any other suitable attachment method. Any number of flow channels 23 may be attached to inner bowl 22. Alternatively, flow channel 23 may be attached to a single walled vessel as described with reference to FIG. 1.

FIG. 6 presents yet another non-limiting example in which the manifold assembly 15 previously described in FIG. 2A is combined with the dual-walled vessel described with respect to FIG. 4A.

FIG. 7 presents another non-limiting example wherein an air source 50 supplies a suitable volume of air through supply line 51 to motor 11. As previously indicated, motor 11 may be an air-driven motor. Any suitable air source may be used including, but not limited to a refillable and/or replaceable storage tank and a compressor.

FIGS. 8A-8D illustrate non-limiting examples wherein firepit 85 has a dual-walled vessel 86 having an inner bowl 81 and an outer bowl 83. Inner bowl 81 has a flow channel 82 formed therein. Flow channel 82 may be formed using any suitable manufacturing technique. In FIG. 8 B, flow channel 82 has a plate 88 forming the remaining side to form a closed flow conduit. In another example, FIG. 8 C shows a modified inner bowl 83′ having a formed section 89 such that channel 82 and section 89 form a flow conduit. In yet another example, FIG. 8 D shows inner bowl 81′ formed with a channel 82′ that extends to outer bowl 83 such that they form a flow conduit for air flow 8. Edges 84 and 84′ may be firmly attached to outer bowls 83′ and 83 respectively by welding, brazing, soldering, or any other suitable technique.

In another non-limiting example, see FIG. 9, firepit 95 has curvilinear flow conduits 90 shaped to provide additional heat transfer area for air flow 8 to pass through. This additional area provides enhanced heating of flow 8 as it passes through conduits 90.

In even another non-limiting example, FIG. 10 shows firepit 105 with flow conduits 101 having a vertically elongated cross-section as compared to the conduits described previously. Such a geometry may provide additional heat transfer area as compared to conduits having a substantially horizontally elongated cross-section as shown in FIGS. 1-9.

In another non-limiting example, FIG. 11 shows firepit 115 with curved vertically elongated conduits 110 that project through the walls of bowl 111 and stand 112. Such an arrangement may reduce the flow frictional losses in conduits 110 and provide enhanced heated area coverage.

While various embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the scope of the invention. Accordingly, it is to be understood that the examples of this disclosure have been presented by way of illustrations and not limitation. 

1. An outdoor firepit, comprising: a vessel adapted to contain a combustible material; a plurality of conduits within the vessel and positioned to be in thermal communication with the combustible material; and an air source forcing air through the plurality of conduits and into an area surrounding the firepit.
 2. The outdoor firepit of claim 1, wherein the plurality of conduits comprises a plurality of flow channels attached to the vessel.
 3. The outdoor firepit of claim 1, wherein the plurality of conduits comprise a manifold assembly engaging the vessel.
 4. The outdoor firepit of claim 1, wherein the each conduit further comprises a conduit nozzle proximate an exit to the conduit.
 5. The outdoor firepit of claim 4, wherein the exit velocity of the air flow is in the range of about 5 to about 40 feet per second.
 6. The outdoor firepit of claim 1, wherein the vessel is a dual-walled vessel having a space between a first wall and a second wall.
 7. The outdoor firepit of claim 6, wherein the space between the first wall and the second wall has an insulating material therein.
 8. The outdoor firepit of claim 7, wherein the space between the first wall and the second wall has a vacuum therein.
 9. The outdoor firepit of claim 4, further comprising a movable deflector attached to the nozzle.
 10. The outdoor firepit of claim 1, wherein the air source comprises a bladed air-moving device.
 11. The outdoor firepit of claim 10, wherein the air source further comprises a motor coupled to the fan.
 12. The outdoor firepit of claim 1, wherein the motor is chosen from the group consisting of: an AC motor, a DC motor, and an air motor.
 13. The outdoor firepit of claim 1, wherein the plurality of conduits comprises a plurality of flow channels at least partially formed into a wall of the vessel.
 14. The outdoor firepit of claim 1, further comprising an insulating material applied to a bottom surface of the vessel.
 15. An apparatus for heating an outdoor area comprising: a vessel adapted to contain a combustible material, the vessel having an inner bowl and an outer bowl and a space therebetween; a plurality of conduits adjacent the inner bowl and positioned to be in thermal communication with the combustible material; and an air source forcing air through the plurality of conduits and into the outdoor area surrounding the vessel.
 16. The apparatus of claim 15, further comprising a thermal insulating material disposed in the space between the outer bowl and the inner bowl.
 17. The apparatus of claim 15, wherein the plurality of conduits comprises a plurality of flow channels at least partially attached to the vessel.
 18. The apparatus of claim 15, wherein the plurality of conduits comprise a manifold assembly engaged with the vessel.
 19. The apparatus of claim 15, wherein the air source comprises a bladed air-moving device.
 20. The apparatus of claim 19, wherein the air source further comprises a motor wherein the motor is chosen from the group consisting of: an AC motor, a DC motor, and an air motor.
 21. The apparatus of claim 15, wherein the plurality of conduits comprises a plurality of flow channels at least partially formed into a wall of the vessel. 